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                                                                             Mathematics  Form 3  Chapter 4 Scale Drawings       Mathematics  Form 3  Chapter 5 Trigonometric Ratio
                       4.  (a)  (i)   Scale                                                                                     CHAPTER
                                   = area of drawing : Actual area        HOTS Challenge                                        5            Trigonometric Ratios
                                     = 400 : 25                                                                                              Nisbah Trigonometri
                                    = 20 : 5                           Length of bedroom 1 in the plan
                                  = 1 :  1                             = (16 – 5 – 2(2.5))
                                       4                               = 6 cm
                                                                                                                              1.  (a)  (i)  adjacent side / sisi bersebelahan    6.  (a)  True
                              (ii)  New scale                          Width of bedroom 1 in the plan                                                                             (b)  False
                                  = Length of drawing : actual length  = 3 + 3                                                       (ii)  opposite side/ sisi bertentangan
                                  = 2 : 4                              = 6 cm                                                        (iii)  hypotenuse / hipotenus                (c)  False
                                                                                                                                                                                  (d)  False
                                  = 1 : 2
                                                                            6          1                                         (b)  (i)   opposite   =   BC                     (e)  True
                                                                                    =                                                     adjacent    AB
                         (b)  length of square = 324                 Actual length  50
                                             = 18 cm                     Actual length = 6 × 50 cm                                   (ii)   opposite   =   BC                   7.  (a)  sin 30° =   PQ
                                                                                    = 300 cm                                              hypotenuse    AC                                       PR
                              length of drawing   1
                                                =                                   = 3 m                                                  adjacent     AB                                 PQ
                                 actual length    4                                                                                  (iii)   hypotenuse   =   AC                           PR   = 0.50
                                        18        1                    Actual width = 3 m
                                                =                                                                                                                                          PQ
                                   actual length  4                                                                                                                                        10   = 0.50
                                   actual length = 4 × 18              Area of bedroom 1 = 3 × 3                              2.  (a)                               5                      PQ = 0.50 × 10

                                                                                         = 9 m
                                                                                               2
                                                = 72 cm                                                                                 tan θ                      13                         = 5 cm
                                  Height of drawing        40                                                                                                       5
                          (c)  (i)                   =                                                                                  sin θ                                                 AB
                                     actual length     2.8 × 1 000                                                                                                 12           8.  (a)  cos x =
                                                       1                                                                                                                                      BC
                                                     =
                                                       70                                                                               cos θ                      12                       =   12
                                               Scale = 1 : 70                                                                                                      13                         13
                                                                                                                                                                                       AB : BC = 12 : 13
                                                                                                                                                                                               = 24 : BC
                                           42             1                                                                                       6    3
                              (ii)                      =                                                                     3.  (a)  sin θ =   O   =    =                            BC = 13 × 2
                                  length of white board   70                                                                                H    10    5
                                  length of white board = 42 × 70                                                                            A    8    4                                  = 26 cm
                                                                                                                                                                                               2
                                                        = 2 940 mm                                                               (b)  cos θ =   H  =  10  =   5                          AC = 26  – 24 2
                                                        = 294 cm                                                                             O    6   3                                   = 10 cm
                                                                                                                                 (a)  tan θ =    =   =
                                  Length of  white board  : width of                                                                         A    8   4                                        3
                                  white board                                                                                                                                     (b)   sin x  =   4
                                  = 3 : 2                                                                                                                                               9    3
                                  = 294 : 196                                                                                 4.  (a)  cos 29° = 0.8746                                AC   =   4
                                                                                                                                 (b)  tan 80° = 5.671
                                  Width of white board = 196 cm                                                                  (c)  sin 50° = 0.7660                                     =   9 × 4
                                                                                                                                                                                               3
                                  Total length of red ribbon needed                                                                                                                        = 12 cm
                                  = (294 × 2) + (196 × 2)
                                                                                                                                            –1
                                  = 980 cm                                                                                    5.  (a)  θ	= cos 0.55
                                                                                                                                       = 56.63°                                   (c)  Let MB be a line perpendicular to BC
                                                                                                                                                                                                2
                                                                                                                                                                                                    2
                                                                                                                                            –1
                                                                                                                                 (b)  θ	= tan 0.15                                     AM = 10  – 8  = 6 cm
                                                                                                                                       = 8.53°                                                MB
                                                                                                                                                                                       tan z =
                                                                                                                                 (c)  θ	= sin 0.87                                            AM
                                                                                                                                           –1
                                                                                                                                       = 60.46°                                             =   8
                                                                                                                                                                                              6
                                                                                                                                                                                              4
                                                                                                                                                                                            =
                                                                                                                                                                                              3

                                                                   19                          © Penerbitan Pelangi Sdn. Bhd.  © Penerbitan Pelangi Sdn. Bhd.              20

                                                                                                                     A11



                BOOKLET ANS MATH F3.indd   11                                                                                                                                                                    03/01/2020   10:20 AM
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